Tony Blair has pitched for historic Sinn Féin backing for the PSNI with a promise that the British security service, MI5, will not be involved in "civic policing" in Northern Ireland.
The British prime minister delivered this apparently crucial assurance in a statement yesterday, ahead of what he hopes will be a weekend commitment by the Sinn Féin leadership to commit to a special ardfheis to finally resolve the policing issue before the end of the month.
Defining the relationship between MI5 and the PSNI essentially in terms of "liaison", Mr Blair said: "All necessary interaction between the security service and PSNI, for example in response to the threat of international terrorism, will, as directed by the Chief Constable, by way of liaison."
His written parliamentary statement went on: "No police officers will be seconded to or under the control of the security service. The small number of police officers who act in a liaison capacity with the security service will be PSNI headquarters staff acting in that role for fixed time-limited periods to the extent that the Chief Constable deems necessary for them to perform their duties."
And, Mr Blair assured: "Policing is the responsibility solely of the PSNI. The security service will have no role whatsoever in civic policing."
That assurance was welcomed by Sinn Féin's Gerry Kelly, who claimed policing would now be protected from what he called the "malign and corruptive control of MI5".
Mr Blair was also encouraged to believe the political process aimed at restoring devolution was still on track by a sanguine DUP response to his confirmation that the PSNI and MI5 would be operating as "completely distinct and entirely separate bodies".
With MI5 due to assume the lead responsibility for "national security intelligence" in the North later this year, Mr Blair's purpose was to assure Sinn Féin that MI5 would not be operating as "a force within a force" in its dealings with the PSNI.
While a war of words raged between Sinn Féin and the SDLP over accountability and scrutiny of the role of the security service, the DUP leadership line was reflected in the Commons by MP Jeffrey Donaldson.
The Lagan Valley MP sought and received an assurance from Mr Blair that there was nothing in yesterday's statement which would "in any way compromise [ British] national security".
The unionist leadership's seeming confidence was also reflected by Ian Paisley jnr. He suggested Sinn Féin president Gerry Adams had been "sold a pup", while maintaining Mr Blair's words amounted to "a re-statement of the fundamentals set out in Annex E of the St Andrews Agreement".
However, that confident assertion by Mr Paisley underlined the sensitivity surrounding yesterday's statement - with Downing Street resisting efforts to clarify the situation and to establish whether Mr Blair's statement involved any significant departure from the St Andrews text.
Asked if anything was fundamentally changed from St Andrews, Mr Blair's official spokesman said: "What this is is a clarification. There is a genuine [ Sinn Féin] concern that those police officers who liaise with the security service should be accountable like any other police officer . . . " Pressed as to whether the key provisions of the St Andrews text held, the spokesman replied: "The substance remains . . . there's no great mystery to this . . . but this is an important qualification."
Asked specifically about the Annex E description of "new integrated working arrangements" involving the security service and PSNI officers, the spokesman would only say these were matters for the Chief Constable to decide in the knowledge that liaison would not compromise police accountability. In respect of the previously published provision for PSNI to run the great majority of national security agents "under the strategic direction" of MI5, the spokesman reiterated "the situation remains as set out" and that, as per Mr Blair's statement yesterday, "these are distinctive services."
Mr Blair's spokesman told The Irish Times he would not break his rules and discuss "intelligence operations" when asked to confirm whether MI5 would have a continuing role in respect of dissident republican terrorism, any resurgent Provisional IRA activity, or organised criminal activity linked to terrorism.
In his statement Mr Blair said the new arrangements "will help bring Northern Ireland into line with a European approach".